<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP 4.3.2 or newer
 *
 * @package		CodeIgniter
 * @author		ExpressionEngine Dev Team
 * @copyright	Copyright (c) 2006 - 2011 EllisLab, Inc.
 * @license		http://codeigniter.com/user_guide/license.html
 * @link		http://codeigniter.com
 * @since		Version 2.0
 * @filesource
 */

// ------------------------------------------------------------------------

/**
 * CodeIgniter Caching Class
 *
 * @package		CodeIgniter
 * @subpackage	Libraries
 * @category	Core
 * @author		ExpressionEngine Dev Team
 * @link
 */
class CI_Cache extends CI_Driver_Library {

	protected $valid_drivers 	= array(
		'cache_apc', 'cache_file', 'cache_memcached', 'cache_dummy'
		);

		protected $_cache_path		= NULL;		// Path of cache files (if file-based cache)
		protected $_adapter			= 'dummy';
		protected $_backup_driver;

		// ------------------------------------------------------------------------

		/**
		 * Constructor
		 *
		 * @param array
		 */
		public function __construct($config = array())
		{
			if ( ! empty($config))
			{
				$this->_initialize($config);
			}
		}

		// ------------------------------------------------------------------------

		/**
		 * Get
		 *
		 * Look for a value in the cache.  If it exists, return the data
		 * if not, return FALSE
		 *
		 * @param 	string
		 * @return 	mixed		value that is stored/FALSE on failure
		 */
		public function get($id)
		{
			return $this->{$this->_adapter}->get($id);
		}

		// ------------------------------------------------------------------------

		/**
		 * Cache Save
		 *
		 * @param 	string		Unique Key
		 * @param 	mixed		Data to store
		 * @param 	int			Length of time (in seconds) to cache the data
		 *
		 * @return 	boolean		true on success/false on failure
		 */
		public function save($id, $data, $ttl = 60)
		{
			return $this->{$this->_adapter}->save($id, $data, $ttl);
		}

		// ------------------------------------------------------------------------

		/**
		 * Delete from Cache
		 *
		 * @param 	mixed		unique identifier of the item in the cache
		 * @return 	boolean		true on success/false on failure
		 */
		public function delete($id)
		{
			return $this->{$this->_adapter}->delete($id);
		}

		// ------------------------------------------------------------------------

		/**
		 * Clean the cache
		 *
		 * @return 	boolean		false on failure/true on success
		 */
		public function clean()
		{
			return $this->{$this->_adapter}->clean();
		}

		// ------------------------------------------------------------------------

		/**
		 * Cache Info
		 *
		 * @param 	string		user/filehits
		 * @return 	mixed		array on success, false on failure
		 */
		public function cache_info($type = 'user')
		{
			return $this->{$this->_adapter}->cache_info($type);
		}

		// ------------------------------------------------------------------------

		/**
		 * Get Cache Metadata
		 *
		 * @param 	mixed		key to get cache metadata on
		 * @return 	mixed		return value from child method
		 */
		public function get_metadata($id)
		{
			return $this->{$this->_adapter}->get_metadata($id);
		}

		// ------------------------------------------------------------------------

		/**
		 * Initialize
		 *
		 * Initialize class properties based on the configuration array.
		 *
		 * @param	array
		 * @return 	void
		 */
		private function _initialize($config)
		{
			$default_config = array(
				'adapter',
				'memcached'
				);

				foreach ($default_config as $key)
				{
					if (isset($config[$key]))
					{
						$param = '_'.$key;

						$this->{$param} = $config[$key];
					}
				}

				if (isset($config['backup']))
				{
					if (in_array('cache_'.$config['backup'], $this->valid_drivers))
					{
						$this->_backup_driver = $config['backup'];
					}
				}
		}

		// ------------------------------------------------------------------------

		/**
		 * Is the requested driver supported in this environment?
		 *
		 * @param 	string	The driver to test.
		 * @return 	array
		 */
		public function is_supported($driver)
		{
			static $support = array();

			if ( ! isset($support[$driver]))
			{
				$support[$driver] = $this->{$driver}->is_supported();
			}

			return $support[$driver];
		}

		// ------------------------------------------------------------------------

		/**
		 * __get()
		 *
		 * @param 	child
		 * @return 	object
		 */
		public function __get($child)
		{
			$obj = parent::__get($child);

			if ( ! $this->is_supported($child))
			{
				$this->_adapter = $this->_backup_driver;
			}

			return $obj;
		}

		// ------------------------------------------------------------------------
}
// End Class

/* End of file Cache.php */
/* Location: ./system/libraries/Cache/Cache.php */